Causes for differing amounts of dirt staining

[Pirarucu]

Obviously the dirt itself and what it's composed of is a part of it, and most of the time is not within the keeper's control, if they only have one option. I think it would be interesting to see what other more controllable factors we can think of for those keepers who would like to see more of their monitor's real colors. To most of us, it isn't a big issue, but at lets say a zoological facility, where appearance is a big part of caging, many monitors are kept in sub-par conditions because housing them properly would get them covered in dirt.

I have thought of two major solutions so far, though both require considerable funding.

Large, running water features:
The application is obvious. The monitor gets in, dirt and dust comes off and is filtered out of the water. Water areas which the monitor keeps dirty or that do not allow the monitor to fully submerge would not allow for this as easily. Larger water features have added benefit of allowing the monitor to excercise.
The Croc Monitor at Moody gardens has a large waterfall and pond which he can submerge and even swim in. He doesn't get dirty on the level that burrowing monitors do, but he does eventually get dusty and a bit dulled down. Once he goes for a swim though, he glows when he gets out. I will also use Aja Michelle's Savs as an example, as she has a large filtered water area and both of hers are quite clean.
This is the best example I have of the Croc at Moody, but as always, cameras don't do justice to a monitor's colors.



Now, on to the second. Live plants:
Obviously, this one is even harder to achieve, though it is doable. You simply need a large enough cage and smart plant selection. I noticed that while monitors in captivity vary in their dirtiness depending on the dirt, wild monitors are almost never dirty, and so I looked for a reason. The conclusion I have come to is the abundance of live plants in wild habitats, or rather, the abundance of roots. It's reasonable to assume that not all dirt throughout their range is "clean", and they don't all have running water to wash up in. (And when they do, it's usually filthy.) Therefore, the only real possibility is plants. Sure enough, when looking at captive monitors, those with plants are cleaner:


When Wayne's plants started disappearing, so did LF and Cera's spots: (Yes, less frequent shedding is another cause.)



Nessie Eating Some Live Crickets - YouTube



So, why does this have such a marked effect? The answer has to do with erosion. One of the chief things preventing erosion in many areas is the abundance of plant life, and when it is taken away, erosive forces go to town. This is because the plant's roots hold the dirt together very well. On a smaller scale, dust, grit, and the small stuff does not escape from the larger particles, and does not get on your monitor, where it dries and cements to the skin when the monitor basks. Here is a perfect example of the effect I am talking about:

On another note, less dust is probably a plus for the monitor's respiratory system.

So, thoughts? Anyone else have other ideas how a nice display could be set up while the monitor's needs are still being met?